FIELD OF THE INVENTION
[0001] The present invention relates to pharmaceuticals. Specifically, the present invention
relates to novel glucokinase activator compounds of Formula I and their pharmaceutically
acceptable salts thereof, exhibiting therapeutic activity and acting as anti-diabetic agents. The
present invention further relates to process for preparation of compounds of Formula I. The
present invention also relates to in silico evaluation of the compounds of Formula I using
10 AutoDock Vina and AutoDock Tools.
BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the
present invention. It is not an admission that any of the information provided herein is prior art
15 or relevant to the presently claimed invention, or that any publication specifically or implicitly
referenced is prior art.
[0003] The prevalence of T2DM is increasing dramatically worldwide. As per International
Diabetes Federation (IDF), 425 million people were reported with diabetes in 2017 and by 2045,
it is expected that this would rise to 629 million worldwide. Diabetes accounted approximately 4
20 million deaths and at least USD 727 billion were spent globally on health expenditure in 2017
(12% of total spending on adults). Even though several options are available for the treatment of
T2DM, presently, no single oral hypoglycaemic drug is capable of attaining satisfactory, longterm
control of blood sugar in T2DM patients hence making it necessary to use combination of
multiple drugs to accomplish the satisfactory control of blood sugar levels. However multi-drug
25 combinations of hypoglycaemic agents can contribute to a better glycemic control, but they tend
to drop efficiency after some period. Moreover, overdose of hypoglycaemic drugs may possibly
produce severe hypoglycemia and several other serious adverse reactions and these patients
usually need serious medical therapy. Thus there is an urgent need to design novel, potent and
efficient hypoglycaemic agents having pharmacologically distinct mechanism of action which
30 can be utilized as single drug therapy with superior safety. Outcomes of several most recent
2
studies together with favourable clinical reports have showed that allosteric human glucokinase
(GK) activators could be employed as antidiabetic drugs with superior potency and safety.
[0004] GK is a cytoplasmic enzyme which accelerates the breakdown of glucose to glucose-6-
phosphate in the presence of ATP and helps in the maintenance of normal blood glucose levels in
5 humans. In pancreatic β-cells, it plays chief role by controlling glucose-stimulated insulin release
and in liver hepatocyte cells, it controls the sugar metabolism. GK is an emerging target for the
therapeutic management of T2DM patients as it plays a key function in the regulation of
carbohydrate metabolism. GK activators are the novel class of therapeutic agents which activate
GK enzyme and show their hypoglycaemic activity. The maximum drug discovery and
10 development programmes linked to synthesis of GK activators as contrived from literature
survey of GK activators were primarily focused on the benzamide derivatives possibly due to
their complementary orientation pattern and binding interactions with the allosteric binding site
of the GK enzyme.
[0005] To date, several GK activators have been reported to decrease Hemoglobin A1c (HbA1c)
15 levels in patients with T2DM. In spite of their positive effects, GK activator treatment has also
been associated with unfavorable effects. Though a number of different glucokinase activator
compounds were being developed, clinical development of glucokinase activators failed due to
the loss of glucose-lowering effects and increased plasma triglyceride levels after chronic
treatment.
20 [0006] There is, therefore, a need to develop new glucokinase activators that can overcome
deficiencies associated with the known compounds. The new glucokinase activators should
exhibit properties such as exert glucose-lowering effects in both insulin-deficient and -resistant
diabetes, and sustain reduced Hemoglobin A1c levels without affecting hepatic and plasma
triglycerides even after chronic treatment.
25
OBJECTS OF THE INVENTION
[0007] An object of the present invention is to provide glucokinase activator compounds having
anti-diabetic properties.
[0008] Yet another object of the present invention is to provide glucokinase activators that can
30 overcome deficiencies associated with the known compounds.
3
[0009] Another object of the present invention is to provide glucokinase activators that retain
glucose lowering effects even after chronic treatment.
[0010] Another object of the present invention is to provide glucokinase activators, with
improved efficacy and better safety profile.
5 [0011] Another object of the present invention is to provide glucokinase activators with high
therapeutic activity and less toxic effects.
[0012] Another object of the present invention is to provide benzamide based glucokinase
activators.
[0013] The other objects and preferred embodiments and advantages of the present invention
10 will become more apparent from the following description of the present invention when read in
conjunction with the accompanying examples and figures, which are not intended to limit scope
of the present invention in any manner.
SUMMARY OF THE INVENTION
15 [0014] This summary is provided to introduce a selection of concepts in a simplified form that
are further described below in Detailed Description section. This summary is not intended to
identify key features or essential features of the claimed subject matter, nor is it intended to be
used as an aid in determining the scope of the claimed subject matter.
[0015] The present invention relates to pharmaceuticals. Specifically, the present invention
20 relates to novel compounds of Formula I, exhibiting therapeutic activity and acting as antidiabetic
agents.
[0016] In one aspect, the present invention relates to novel compounds of Formula I, acting as
glucokinase activators.
[0017] In another aspect, the present invention relates to novel compounds of Formula I, useful
25 as anti-diabetic agents, with improved efficacy and better safety profile.
[0018] In another aspect, the present invention relates to novel compounds of Formula I, useful
as anti-diabetic agents, with high therapeutic activity and less toxic effects.
[0019] In one aspect, the present invention relates to compounds of Formula I, and their
pharmaceutically acceptable salts thereof,
4
O N-^\ / ;
H H
O'S"NH-R
Formula I
wherein:
R can be selected from H, C1-6alkyl, C3-7cycloalkyl or C6-10aryl; wherein the said C1-6alkyl, C3-
7cycloalkyl, C6-10aryl may optionally be substituted at any available position by one or more
5 suitable substituents selected from R1;
R1 can be selected from H, C1-6alkyl, -OH, -NH2, -CHO, -NO2, -F, -Cl, -Br, -I, -COOH or -
CONH2.
[0020] In another aspect, the present invention relates to benzimidazole substituted
benzamide analogues of Formula I as allosteric activators of human glucokinase.
10 [0021] In another aspect, the present invention relates to compounds of Formula I, wherein
R can be selected from C1-6alkyl or C6-10aryl.
[0022] In another aspect, the present invention relates to compounds of Formula I wherein
wherein R1 can be selected from H, C1-6alkyl, C6-10aryl, -OH, -NH2, -NO2, -F or -Br.
[0023] In another aspect, the invention also relates to the processes for the synthesis of
15 novel compounds of Formula I and their pharmaceutically acceptable salts thereof.
[0024] In yet another aspect, the present invention relates to in silico evaluation of
compounds of Formula I, using AutoDock Vina and AutoDock Tools.
[0025] In still another aspect, the present invention relates to in vitro evaluation of the
compounds of Formula I, for their GK activation potential using enzymatic assay.
20 [0026] Other aspects of the invention will be set forth in the description which follows, and in
part will be apparent from the description, or may be learnt by the practice of the invention.
DETAILED DESCRIPTION
[0027] The following is a detailed description of embodiments of the disclosure. The
25 embodiments are in such detail as to clearly communicate the disclosure. However, the amount
of detail offered is not intended to limit the anticipated variations of embodiments; on the
5
contrary, the intention is to cover all modifications, equivalents, and alternatives falling within
the spirit and scope of the present disclosure as defined by the appended claims.
[0028] All publications herein are incorporated by reference to the same extent as if each
individual publication or patent application were specifically and individually indicated to be
5 incorporated by reference. Where a definition or use of a term in an incorporated reference is
inconsistent or contrary to the definition of that term provided herein, the definition of that term
provided herein applies and the definition of that term in the reference does not apply.
[0029] Reference throughout this specification to “one embodiment” or “an embodiment”
means that a particular feature, structure or characteristic described in connection with the
10 embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one
embodiment” or “in an embodiment” in various places throughout this specification are not
necessarily all referring to the same embodiment. Furthermore, the particular features, structures,
or characteristics may be combined in any suitable manner in one or more embodiments.
[0030] In some embodiments, the numbers expressing quantities of ingredients, properties
15 such as concentration, reaction conditions, and so forth, used to describe and claim certain
embodiments of the invention are to be understood as being modified in some instances by the
term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the
written description and attached claims are approximations that can vary depending upon the
desired properties sought to be obtained by a particular embodiment. In some embodiments, the
20 numerical parameters should be construed in light of the number of reported significant digits
and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and
parameters setting forth the broad scope of some embodiments of the invention are
approximations, the numerical values set forth in the specific examples are reported as precisely
as practicable. The numerical values presented in some embodiments of the invention may
25 contain certain errors necessarily resulting from the standard deviation found in their respective
testing measurements.
[0031] As used in the description herein and throughout the claims that follow, the meaning
of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise.
Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the
30 context clearly dictates otherwise.
6
[0032] Unless the context requires otherwise, throughout the specification which follow,
the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be
construed in an open, inclusive sense that is as “including, but not limited to.”
[0033] The recitation of ranges of values herein is merely intended to serve as a shorthand
5 method of referring individually to each separate value falling within the range. Unless otherwise
indicated herein, each individual value is incorporated into the specification as if it were
individually recited herein. All methods described herein can be performed in any suitable order
unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any
and all examples, or exemplary language (e.g. “such as”) provided with respect to certain
10 embodiments herein is intended merely to better illuminate the invention and does not pose a
limitation on the scope of the invention otherwise claimed. No language in the specification
should be construed as indicating any non-claimed element essential to the practice of the
invention.
[0034] Groupings of alternative elements or embodiments of the invention disclosed herein
15 are not to be construed as limitations. Each group member can be referred to and claimed
individually or in any combination with other members of the group or other elements found
herein. One or more members of a group can be included in, or deleted from, a group for reasons
of convenience and/or patentability. When any such inclusion or deletion occurs, the
specification is herein deemed to contain the group as modified thus fulfilling the written
20 description of all Markush groups used in the appended claims.
[0035] The description that follows, and the embodiments described therein, is provided by
way of illustration of an example, or examples, of particular embodiments of the principles and
aspects of the present disclosure. These examples are provided for the purposes of explanation,
and not of limitation, of those principles and of the disclosure.
25 [0036] It should also be appreciated that the present disclosure can be implemented in
numerous ways, including as a system, a method or a device. In this specification, these
implementations, or any other form that the invention may take, may be referred to as processes.
In general, the order of the steps of the disclosed processes may be altered within the scope of
the invention.
30 [0037] The headings and abstract of the invention provided herein are for convenience only
and do not interpret the scope or meaning of the embodiments.
7
[0038] The following discussion provides many example embodiments of the inventive
subject matter. Although each embodiment represents a single combination of inventive
elements, the inventive subject matter is considered to include all possible combinations of the
disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second
5 embodiment comprises elements B and D, then the inventive subject matter is also considered to
include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[0039] Various terms as used herein are shown below. To the extent a term used in a claim
is not defined below, it should be given the broadest definition persons in the pertinent art have
given that term as reflected in printed publications and issued patents at the time of filing..
10 [0040] The present invention relates to pharmaceuticals. Specifically, the present invention
relates to novel compounds of Formula I, exhibiting therapeutic activity and acting as antidiabetic
agents.
[0041] In one embodiment, the present invention relates to novel compounds of Formula I,
acting as glucokinase activators.
15 [0042] In another embodiment, the present invention relates to novel compounds of
Formula I, useful as anti-diabetic agents, with improved efficacy and better safety profile.
[0043] In another embodiment, the present invention relates to novel compounds of Formula I,
useful as anti-diabetic agents, with high therapeutic activity and less toxic effects.
[0044] In one embodiment, the present invention relates to compounds of Formula I, and
20 their pharmaceutically acceptable salts thereof,
O N^p)
H H
O'S"NH-R
Formula I
wherein:
R can be selected from H, C1-6alkyl, C3-7cycloalkyl or C6-10aryl; wherein the said C1-6alkyl, C3-
7cycloalkyl, C6-10aryl may optionally be substituted at any available position by one or more
25 suitable substituents selected from R1;
8
R1 can be selected from H, C1-6alkyl, C3-7cycloalkyl, C6-10aryl -OH, -NH2, -CHO, -NO2, -F, -Cl, -
Br, -I, -COOH or -CONH2.
[0045] In another embodiment, the present invention relates to benzimidazole substituted
benzamide analogues of Formula I as allosteric activators of human glucokinase.
5 [0046] In a preferred embodiment, the present invention relates to compounds of Formula
I, wherein R can be selected from C1-6alkyl or C6-10aryl.
[0047] In another preferred embodiment, the present invention relates to compounds of
Formula I wherein R1 can be selected from H, C1-6alkyl, C6-10aryl, -OH, -NH2, -NO2, -F or –Br.
10 DEFINITIONS
[0048] Relative to the above description of the compounds of the present invention, the
following definitions apply.
[0049] The term “alkyl” as used herein alone or as part of another group refers to a
straight or branched chain aliphatic hydrocarbon chain, having from 1 to 6 carbon atoms.
15 Examples of alkyl include, but are not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, npentyl,
t-butyl and the like. Alkyl groups may further be substituted with one or more suitable
substituents.
[0050] The term “cycloalkyl” refers to cyclic alkyl groups constituting of 3 to 7 carbon
atoms. Such cycloalkyl groups include, by way of example, single ring structures, for example,
20 cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. Cycloalkyl groups may further be
substituted with one or more suitable substituents. The term “cycloalkyl” may optionally contain
one or more unsaturated bonds.
[0051] The term “aryl” herein refers to six to ten membered monocyclic aromatic group, for
example phenyl or naphthyl ring and the like optionally substituted with one or more suitable
25 substituents. The aryl group may optionally be fused with one or two cycloalkyl group(s) or
other aryl group(s) resulting in polycyclic ring system. The fused group may be further substituted
with one or more suitable substituents.
[0052] A “pharmaceutically acceptable salt” refers to salts prepared from pharmaceutically
acceptable non-toxic bases or acids including inorganic or organic bases and inorganic or organic
30 acids. A “pharmaceutically acceptable salt” also encompasses any compound according to the
present invention that is utilized in the form of a salt thereof, especially where the salt confers on
9
5
10
a compound improved pharmacokinetic properties as compared to the free form of compound or
a different salt form of the compound.
[0053] In another embodiment, particularly useful examples of the present invention
include but are not limited to the compounds selected from Table 1:
Compound No.
1
2
3
4
5
6
7
8
9
10
Name
iV (1^-1,3 Benzodiazol 2 yl) 3 (phenylsulfamoyl)benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 [(2 chloro 4 nitrophenyl)sulfamoyl]
benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 (benzylsulfamoyl)benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 (butylsulfamoyl)benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 (methylsulfamoyl)benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 [(2 methylphenyl)sulfamoyl]benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 [(4 bromophenyl)sulfamoyl]benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 [(4 nitrophenyl)sulfamoyl]benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 [(4 methylphenyl)sulfamoyl]benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 (propylsulfamoyl)benzamide
[0054] In another embodiment, the invention also relates to the processes for the synthesis
of novel compounds of Formula I and their pharmaceutically acceptable salts thereof.
[0055] The compounds of the present invention may be prepared by the following reaction
sequences as depicted in for example Scheme 1. The compounds disclosed may also be prepared
by techniques known in the art and familiar to the skilled organic chemist. All of the starting
materials are either commercially available or can be prepared by procedures that would be well
known to one of ordinary skill in organic chemistry.
O
( a )
O
i :i OH (b)
OsS: : ;Cl
O
O H ( c )
O SCNH-R
O
O- VNH-R
( d )
O N•I 6.y y J>
H H
Oj S " N H -R
F o r m u l a I
10
Scheme 1: Synthetic route followed for N-benzimidazol-2-yl benzamide derivatives. Reagents
and conditions: (a) Chlorosulphonic acid, 80 , 2h; (b) NH2-R, reflux; (c) Thionyl chloride,
reflux; (d) 2-Aminobenzimidazole, reflux.
[0056] In one embodiment, Novel benzimidazole substituted benzamide compounds of Formula
5 I and their pharmaceutically acceptable salts thereof, can be synthesized in good yields starting
from benzoic acid (Scheme 1). Benzoic acid was chlorosulphonated to obtain 3-
(chlorosulphonyl) benzoic acid followed by reaction with amines to obtain respective
sulphonamides. The sulphonamides were reacted with SOCl2 to get respective benzoyl chlorides
which were then reacted with the commercially available 2-aminobenzimidazole to obtain the
10 final products. The synthesis as well as purity of synthesized derivatives were ensured by single
spot TLC and further confirmed by spectral analysis.
[0057] In another embodiment, compounds of Formula I are prepared by following steps:
a) chlorosulphonating benzoic acid to obtain 3-(chlorosulphonyl)benzoic acid;
b) reaction of 3-(chlorosulphonyl)benzoic acid with different amines to obtain respective
15 sulphonamides;
c) reacting the sulphonamides obtained in step (b) with SOCl2 to get respective benzoyl
chlorides; and
d) reacting the benzoyl chlorides obtained in step (c) 2-aminobenzimidazole to obtain
compounds of Formula I.
20 [0058] In another embodiment, novel compounds of Formula I with different R groups were
synthesized and characterized as shown in Table 2.
Table 2: Physicochemical properties of the synthesized derivatives.
Compound
No.
1
2
3
4
5
R
-C6H5
C l x ^ v ^ N O 2
-CH2C6H4
-C4H9
-CH3
Mol. formula
C20H15N3O3S2
C20H13ClN4O5S2
C21H17N3O3S2
C18H19N3O3S2
C15H13N3O3S2
M. Pt. (ºC)
152-154
168-171
160-165
143-146
135-138
Rf
*
0.62
0.57
0.56
0.69
0.76
% Yield
66
72
49
59
57
11
6
7
8
9
10
H3C" \ ^
XX
""CI
-C3H7
C21H17N3O3S2
C20H14BrN3O3S2
C21H17N3O3S2
C20H14N4O5S2
C17H17N3O3S2
165-168
172-175
163-166
159-163
165-170
0.48
0.77
0.68
0.64
0.73
77
73
63
67
45
*TLC mobile phase: Toluene: Ethyl acetate (7:3).
[0059] The 1H-NMR spectra of the synthesized comounds showed the singlet signal equivalent
to one proton of CONH functional group at δ 9-10 ppm, thus confirming the formation of amide
linkage in the synthesized derivatives. The presence of singlet signal for one NH proton of
5 SO2NH functional group was observed around δ 2.5 ppm which confirmed the formation of
sulphonamides by the reaction of sulphonyl chloride derivatives with the corresponding amines.
The presence of a singlet signal, two doublet signals and a triplet signal around δ 8 ppm
belonging to the protons at C2, C4, C5 and C6; respectively of the phenyl ring derived from
benzoic acid confirmed that the amide bond and sulphonamide linkage were placed meta to each
10 other i.e., separated by C2. In the 1H-NMR spectra of the synthesized compounds two doublet
signals and two triplet signals corresponding to four aromatic CH protons were observed in the
range δ 7-8 ppm which confirmed that 2-aminobenzimidazole was reacted with benzoyl chloride
derivatives for the synthesis of benzamide derivatives. Occurrence of singlet signal at δ 5 ppm
corresponding to NH of benzimidazol-2-yl further confirmed the presence of benzimidazol-2-yl
15 in the structure of the synthesized compounds. The FTIR spectra of the synthesized benzamide
derivatives showed the presence of amide NH- stretching vibrations around 3300-3200 cm-1;
aromatic CH- stretching vibrations above 3000 cm-1; SO2 asymmetric and symmetric stretching
vibrations around 1400-1300 cm-1 and 1200-1100 cm-1 respectively; and sulphonamide NHstretching
vibrations in the range 3400-3100 cm-1, thus supporting the fact that an amide linkage
20 (CONH) and a sulphonamide functional group (SO2-NH) were present in the structure of the
synthesized molecules. In the FTIR spectra of the synthesized molecules C=O stretching
12
vibrations in the range 1700-1600 cm-1 indicated the presence of amide carbonyl functional
group in the structure of the synthesized benzamide derivatives. The NH- bending vibrations
around 1600 cm-1 were present in the FTIR spectra of the synthesized molecules confirming the
presence of aromatic NH- functional group in the structure of the synthesized molecules.
5 [0060] In another embodiment, the present invention relates to in silico evaluation of
compounds of Formula I, using AutoDock Vina and AutoDock Tools.
[0061] In yet another embodiment, In silico molecular docking studies were performed to
explore the affinity and binding interactions of the designed molecules of Formula I, using
AutoDock Vina in the allosteric binding site of GK protein (PDB ID: 3IMX), which was
10 surrounded by the β1 strand and α5 helix of the large domain, the C-terminal α13 helix of the
small domain, and the GK specific connecting region I (Ser64-Gly72). The reference ligand of
PDB 3IMX was docked into the allosteric site of GK; and the docked reference GK activator
produced a similar binding pattern and superposition on the binding mode of co-crystallized
activator with ΔG of -9.0 kcal/mol validating accuracy of docking methodology. Most of the
15 docked ligands showed appreciable binding in the allosteric site of GK as established by
analyzing their bonding interactions and ΔG of the best docked poses. These compounds
displayed strong H-bond interactions between NH of benzamide and amide carbonyl of Arg63
residue; and N of benzimidazol-2-yl ring and amide NH of Arg63 in the allosteric site of GK
protein.
20 [0062] In still another embodiment, the present invention relates to In vitro evaluation of
the compounds of Formula I, for their GK activation potential using enzymatic assay.
[0063] In yet another embodiment, the GK activity of the compounds of Formula I was
evaluated using a coupled reaction with glucose-6-phosphate dehydrogenase spectrometrically
by measuring absorbance at 340 nm. Amongst the synthesized derivatives, two compounds
25 showed maximum GK activation in the in vitro GK assay (fold activation in the range 1.8 to 2.1
compared to control). Other compounds showed moderate fold activation (around 1.5 compared
to control) of GK enzyme. Based on screening by in vitro GK assay, two compounds were
further evaluated for their blood glucose lowering effects by means of rat oral glucose tolerance
test (OGTT) using metformin as standard antidiabetic drug. The results of antihyperglycemic
30 activity assay depicted that these two compounds potently reduced blood glucose levels at a dose
of 30 mg/kg and 50 mg/kg compared to metformin. These compounds were almost equipotent to
13
the standard antidiabetic drug (metformin) at 30 and 60 min and decreased blood glucose levels
equivalent to that of standard at 120 min interval after glucose load. These compounds were
found to reduce significantly the glucose AUC compared to control (reduction in glucose AUC
in the range 27-29%) and analogous to that of metformin (29% reduction in glucose AUC)
5 (standard antidiabetic drug). All the compounds tested for antihyperglycemic activity reduced
blood glucose in safe range (i.e., no hypoglycaemic effect was observed during assay period i.e.,
0-120 min).
[0064] While the foregoing describes various embodiments of the disclosure, other and
further embodiments of the disclosure may be devised without departing from the basic scope
10 thereof. The scope of the invention is determined by the claims that follow. The invention is not
limited to the described embodiments, versions or examples, which are included to enable a
person having ordinary skill in the art to make and use the invention when combined with
information and knowledge available to the person having ordinary skill in the art.
15 EXAMPLES
[0065] The present invention is further explained in the form of following examples.
However, it is to be understood that the following examples are merely illustrative and are not to
be taken as limitations upon the scope of the invention.
[0066] Example 1: General Scheme for Preparation of Compounds of Formula I
20 [0067] Dry benzoic acid (0.01 mol) was taken in a flask fixed with a magnetic stirrer and
the temperature was kept constant between 10 and 15 ºC using cold water bath. Chlorosulphonic
acid (8.0 mL) was introduced cautiously and checked to confirm no leakage. After whole acid
was dissolved and the exothermic reaction ceased, the reaction flask was heated on water bath at
70-80 for 2 h to complete the reaction followed by cooling. The contents of flask were added
25 to 150 g crushed ice with stirring to break the lumps and precipitates of 3-(chlorosulphonyl)
benzoic acid were filtered under vacuum followed by washing with cold water and air dried. The
product obtained above (0.01 mol) was refluxed with commercially available amines (0.01 mol)
in acetone until reaction completion as monitored by TLC on silica gel G followed by cooling
and precipitates of respective sulphonamides were dried. The various sulphonamides obtained
30 (0.01 mol) were refluxed with thionyl chloride (0.01 mol) for 3 h and excess thionyl chloride was
distilled off to get the respective benzoyl chlorides. Benzoyl chlorides (0.01 mol) obtained above
14
were refluxed with 2-aminobenzimidazole (0.015 mol) in acetone and reaction completion was
monitored using single spot TLC on silica gel G plates. The final products received after the
evaporation of solvent were purified by recrystallization using ethyl alcohol.
[0068] Example 2:
5 Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 (phenylsulfamoyl)benzamide (1): FTIR (KBr
Pellets) ν cm-1: 3867.78 (NH str., CONH), 3737.50 (NH str., CONH), 3432.08.46 (NH str.,
SO2NH), 2973.38 (CH str., Aromatic), 1642.58 (C=O str., CONH), 1558.12 (NH bend, Ar-NH),
1463.36 (C=N str., Aromatic), 1417.54 (C=C str., Aromatic), 1296.70 (SO2 asym. str., SO2NH),
1100.00 (C-N str., Benzimidazol-2-yl), 1076.13 (SO2 sym. str., SO2NH), 752.08 (CH bend,
10 Aromatic); 1H-NMR (δ ppm, 400 MHz, DMSO-d6): 8.92 (s, 1H, NH, CONH), 8.24-8.52 (m,
4H, CH, C2, C4, C5 and C6 of C6H4CO), 7.34-8.26 (m, 4H, CH, C4, C5, C6 and C7 of
Benzimidazol-2-yl), 6.88-7.32 (m, 5H, CH of C2, C3, C4, C5 and C6 of C6H5), 5.00 (s, 1H, NH,
Benzimidazol-2-yl), 4.00 (s, 1H, NH, SO2NH).
[0069] Example 3:
15 Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 [(2 chloro 4 nitrophenyl)sulfamoyl]
benzamide (2): FTIR (KBr Pellets) ν cm-1: 3836.20 (NH str., CONH), 3446.91 (NH str., SO2-
NH), 2928.28 (CH str., Aromatic), 1641.34 (C=O str., CONH), 1632.23 (NH bend, Ar-NH),
1551.35 (C=N str., Aromatic), 1464.11 (NO2 sym. str., NO2), 1413.94 (NO2 asym. str., NO2),
1299.66 (SO2 asym. str., SO2NH), 1100.00 (C-N str., Benzimidazol-2-yl), 1079.66 (SO2 sym.
20 str., Sulphonamide), 684.36 (C-Cl str., Aromatic); 1H-NMR (δ ppm, 400 MHz, DMSO-d6): 9.04
(s, 1H, NH, CONH), 8.02-8.48 (m, 4H, CH, C2, C4, C5 and C6 of C6H4CO), 7.54-8.11 (m, 4H,
CH, C4, C5, C6 and C7 of Benzimidazol-2-yl), 6.98-8.12 (m, 3H, CH of C3, C5 and C6 of
C6H3ClNO2), 5.00 (s, 1H, NH, Benzimidazol-2-yl), 4.00 (s, 1H, NH, SO2NH).
[0070] Example 4:
25 Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 (benzylsulfamoyl)benzamide (3): FTIR (KBr
Pellets) ν cm-1: 3755.80 (NH str., CONH), 3448.08 (NH str., SO2NH), 2996.40 (CH str.,
Aromatic), 2912.85 (CH str., Alkyl), 1659.53 (C=O str., CONH), 1429.38 (NH bend, Ar-NH),
1311.51 (SO2 asym. str., SO2NH), 1100.00 (C-N str., Benzimidazol-2-yl), 1025.25 (SO2 sym.
str., SO2NH), 696.02 (CH bend, Aromatic); 1H-NMR (δ ppm, 400 MHz, DMSO-d6): 8.98 (s,
30 1H, NH, CONH), 8.16-8.42 (m, 4H, CH, C2, C4, C5 and C6 of C6H4CO), 7.68-8.32 (m, 4H,
CH, C4, C5, C6 and C7 of Benzimidazol-2-yl), 7.16-7.58 (m, 5H, CH of C2, C3, C4, C5 and C6
15
of C6H5), 6.24 (t, 1H, NH, SO2NH), 5.00 (s, 1H, NH, Benzimidazol-2-yl), 4.42 (d, 1H, CH,
CH2).
[0071] Example 5:
Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 (butylsulfamoyl)benzamide (4): FTIR (KBr
5 Pellets) ν cm-1: 3754.38 (NH str., CONH), 3448.26 (NH str., SO2NH), 2930.77 (CH str.,
Aromatic), 2962.66 (CH str., Alkyl), 1643.35 (C=O str., CONH), 1554.13 (NH bend, Ar-NH),
1464.82 (C=C str., Aromatic), 1415.35 (SO2 asym. str., SO2NH), 1100.00 (C-N str.,
Benzimidazol-2-yl), 1076.78 (SO2 sym. str., SO2NH); 1H-NMR (δ ppm, 400 MHz, DMSO-d6):
9.08 (s, 1H, NH, CONH), 7.80-8.12 (m, 4H, CH, C2, C4, C5 and C6 of C6H4CO), 7.63-8.38 (m,
10 4H, CH, C4, C5, C6 and C7 of Benzimidazol-2-yl), 5.54 (t, 1H, NH, SO2NH), 5.00 (s, 1H, NH,
Benzimidazol-2-yl), 4.08 (m, 2H, CH2), 2.62 (m, 2H, CH2), 1.78 (m, 2H, CH2), 1.08 (m, 3H,
CH3).
[0072] Example 6:
Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 (methylsulfamoyl)benzamide (5): FTIR (KBr
15 Pellets) ν cm-1: 3798.48 (NH str., CONH), 3448.44 (NH str., SO2NH), 3017.57 (CH str.,
Aromatic), 2966.14 (CH str., Alkyl), 1654.21 (C=O str., CONH), 1598.09 (NH bend, Ar-NH),
1544.68 (C=N str., Aromatic), 1388.45 (SO2 asym. str., SO2NH), 1189.77 (SO2 sym. str.,
SO2NH), 1100.00 (C-N str., Benzimidazol-2-yl), 789.65 (CH bend, Aromatic); 1H-NMR (δ
ppm, 400 MHz, DMSO-d6): 8.88 (s, 1H, NH, CONH), 7.94-8.43 (m, 4H, CH, C2, C4, C5 and
20 C6 of C6H4CO), 7.45-8.16 (m, 4H, CH, C4, C5, C6 and C7 of Benzimidazol-2-yl), 5.34 (t, 1H,
NH, SO2NH), 5.00 (s, 1H, NH, Benzimidazol-2-yl), 2.44 (s, 3H, CH3).
[0073] Example 7:
Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 [(2 methylphenyl)sulfamoyl]benzamide (6):
FTIR (KBr Pellets) ν cm-1: 3791.96 (NH str., CONH), 3456.56 (NH str., SO2NH), 3013.67 (CH
25 str., Aromatic), 2912.67 (CH str., Alkyl), 1667.25 (C=O str., SO2NH), 1604.66 (NH bend, Ar-
NH), 1578.56 (C=N str., Aromatic), 1345.34 (SO2 asym. str., SO2NH), 1103.78 (SO2 sym. str.,
SO2NH), 1100.00 (C-N str., Benzimidazol-2-yl), 850.55 (CH bend, Aromatic); 1H-NMR (δ
ppm, 400 MHz, DMSO-d6): 8.89 (s, 1H, NH, CONH), 8.08-8.43 (m, 4H, CH, C2, C4, C5 and
C6 of C6H4CO), 7.42-8.08 (m, 4H, CH, C4, C5, C6 and C7 of Benzimidazol-2-yl), 6.44-7.25
30 (m, 4H, CH of C2, C3, C4, C5 and C6 of C6H4CH3), 5.00 (s, 1H, NH, Benzimidazol-2-yl), 2.54
(s, 1H, NH, SO2NH), 2.43 (s, 3H, CH3).
16
[0074] Example 8:
Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 [(4 bromophenyl)sulfamoyl]benzamide (7):
FTIR (KBr Pellets) ν cm-1: 3837.14 (NH str., CONH), 3732.98 (NH str., CONH), 3441.64 (NH
str., SO2NH), 2974.87 (CH str., Aromatic), 1641.67 (C=O str., CONH), 1553.91 (NH bend, Ar-
5 NH), 1464.33 (C=N str., Aromatic), 1415.88 (SO2 asym. str., SO2NH), 1296.76 (SO2 sym. str.,
SO2NH), 1100.00 (C-N str., Benzimidazol-2-yl), 809.70 (CH bend, Aromatic), 753.82 (C-Br
str., Aromatic); 1H-NMR (δ ppm, 400 MHz, DMSO-d6): 8.75 (s, 1H, NH, CONH), 8.14-8.38
(m, 4H, CH, C2, C4, C5 and C6 of C6H4CO), 6.85-8.03 (m, 4H, CH, C4, C5, C6 and C7 of
Benzimidazol-2-yl), 7.06-7.38 (m, 4H, CH of C2, C3, C5 and C6 of C6H4Br), 5.00 (s, 1H, NH,
10 Benzimidazol-2-yl), 2.59 (s, 1H, NH, SO2NH).
[0075] Example 9:
Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 [(4 nitrophenyl)sulfamoyl]benzamide (8):
FTIR (KBr Pellets) ν cm-1: 3870.59 (NH str., CONH, 3755.40 (NH str., CONH), 3452.66 (NH
str., SO2NH), 2997.49 (CH str., Aromatic), 1708.27 (C=O str., CONH), 1429.03 (NO2 sym.
15 str.), 1362.55 (NO2 asym. str.), 1311.98 (SO2 asym. str., SO2NH), 1223.02 (SO2 sym. str.,
SO2NH), 1100.00 (C-N str., Benzimidazol-2-yl), 696.02 (CH bend, Aromatic); 1H-NMR (δ
ppm, 400 MHz, DMSO-d6): 8.84 (s, 1H, NH, CONH), 8.28-8.58 (m, 4H, CH, C2, C4, C5 and
C6 of C6H4CO), 7.89-8.17 (m, 4H, CH, C4, C5, C6 and C7 of Benzimidazol-2-yl), 6.68-7.85
(m, 4H, CH of C2, C3, C5 and C6 of C6H4NO2), 5.00 (s, 1H, NH, Benzimidazol-2-yl), 2.50 (s,
20 1H, NH, SO2NH).
[0076] Example 10:
Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 [(4 methylphenyl)sulfamoyl]benzamide (9):
FTIR (KBr Pellets) ν cm-1: 3868.16 (NH str., CONH), 3754.28 (NH str., CONH), 3448.36 (NH
str., SO2NH), 2930.77 (CH str., Aromatic), 1643.31 (C=O str., CONH), 1553.03 (NH bend, Ar-
25 NH), 1464.83 (C=N str., Aromatic), 1415.35 (CH bend, Alkyl), 1300.62 (SO2 asym. str.,
SO2NH), 1100.00 (C-N str., Benzimidazol-2-yl), 1076.79 (SO2 sym. str., SO2NH), 717.52 (CH
bend, Aromatic); 1H-NMR (δ ppm, 400 MHz, DMSO-d6): 8.76 (s, 1H, NH, CONH), 7.98-8.28
(m, 4H, CH, C2, C4, C5 and C6 of C6H4CO), 7.32-7.75 (m, 4H, CH, C4, C5, C6 and C7 of
Benzimidazol-2-yl), 6.32-7.23 (m, 4H, CH of C2, C3, C4, C5 and C6 of C6H4CH3), 5.00 (s, 1H,
30 NH, Benzimidazol-2-yl), 4.00 (s, 1H, NH, SO2NH), 2.36 (s, 3H, CH3).
17
[0077] Example 11:
Preparation of N (1H-1,3 Benzodiazol 2 yl) 3 (propylsulfamoyl) benzamide (10): FTIR
(KBr Pellets) ν cm-1: 3450.06 (NH str., CONH), 2996.68 (NH str., SO2NH), 2912.98 (CH str.,
Aromatic), 1689.51 (C=O str., CONH), 1428.92 (NH bend, Ar-NH), 1311.73 (C=N str.,
5 Aromatic), 1100.00 (C-N str., Benzimidazol-2-yl), 1023.65 (SO2 asym. str., SO2NH), 950.47
(SO2 sym. str., SO2NH), 696.27 (CH bend, Aromatic); 1H-NMR (δ ppm, 400 MHz, DMSO-d6):
9.11 (s, 1H, NH, CONH), 8.20-8.43 (s, 3H, CH, C2, C4 and C6 of C6H3CO), 7.58-8.12 (m, 4H,
CH, C4, C5, C6 and C7 of Benzimidazol-2-yl), 5.00 (s, 1H, NH, Benzimidazol-2-yl), 4.00 (s,
1H, NH, SO2NH), 3.94 (m, 2H, CH2), 2.65 (m, 2H, CH2), 1.24 (t, 3H, CH3).
10 [0078] Example 12:
In silico Docking Studies: Molecular docking studies were carried out for the synthesized
derivatives in the allosteric binding site of the GK protein (PDB ID: 3IMX) using AutoDock
Vina and AutoDock Tools. The 2D chemical structures of all the ligands were prepared by
Marvin Sketch followed by conversion to to 3D by Frog2 server. The ligands were converted to
15 “pdbqt” files using AutoDock Tools. After assessing a numbers of co-crystallized structures for
the target proteins available in the protein data bank; the best ligand bound complex was selected
based on higher resolution and key binding interactions between the ligands and proteins. The
PDB file of GK protein were edited using PyMOL (PyMOL Molecular Graphics System,
Schrödinger, LLC.) by removing the co-crystallized activator, all the water molecules as well as
20 all non-interacting ions. The “pdbqt” files of target proteins were generated from the PDB files
using AutoDock Tools. The grid parameters were calculated using “Grid” tool of AutoDock
Tools and all the data regarding target protein, ligand, grid size and geometry were saved in “txt”
file. Docking was performed using command line on Windows 10 computer. The reference
ligands were docked in the binding site of the target proteins and compared with that of co-
25 crystallized ligands for determining accuracy of docking protocol. The 3-D optimized ligands
were docked in the binding site of the refined protein models and scored by scoring function.
The binding free energy (ΔG, kcal/mol) for each ligand was reported in log file and the binding
interactions of the ligands in binding site of the target proteins were analysed using PyMOL.
[0079] Example 13:
30 In vitro GK Assay: The in vitro GK activity of the synthesized compounds was evaluated using
a coupled reaction with glucose-6-phosphate dehydrogenase spectrophotometrically at 340 nm.
18
All the synthesized compounds were dissolved in dimethyl sulfoxide (DMSO) and the assay was
performed in a final volume of 2000 μL containing 2-(4-(2-hydroxyethyl)piperazin-1-yl)
ethanesulfonic acid (25 mM, pH 7.4), glucose (10 mM), potassium chloride (25 mM),
magnesium chloride (1 mM), dithiothreitol (1 mM), adenosine tri-phosphate (1 mM),
5 nicotinamide-adenine dinucleotide (1 mM), G-6-PDH (2.5 U/mL), GK (0.5 μg), and compounds
under investigation (10 μM). Absorbance was measured at 340 nm after 3 min incubation period
and GK activation fold for the synthesized compounds was calculated compared to control (GK
activation by DMSO only was considered as 100%).
[0080] Amongst the synthesized derivatives, two compounds showed maximum GK activation
10 in the in vitro GK assay (fold activation in the range 1.8 to 2.1 compared to control). Other
compounds showed moderate fold activation (around 1.5 compared to control) of GK enzyme.
Based on screening by in vitro GK assay, two compounds were further evaluated for their blood
glucose lowering effects by means of rat oral glucose tolerance test (OGTT) using metformin as
standard antidiabetic drug. The results of antihyperglycemic activity assay depicted that these
15 two compounds potently reduced blood glucose levels at a dose of 30 mg/kg and 50 mg/kg
compared to metformin. These compounds were almost equipotent to the standard antidiabetic
drug (metformin) at 30 and 60 min and decreased blood glucose levels equivalent to that of
standard at 120 min interval after glucose load. These compounds were found to reduce
significantly the glucose AUC compared to control (reduction in glucose AUC in the range 27-
20 29%) and analogous to that of metformin (29% reduction in glucose AUC) (standard antidiabetic
drug). All the compounds tested for antihyperglycemic activity reduced blood glucose in safe
range (i.e., no hypoglycaemic effect was observed during assay period i.e., 0-120 min).
[0081] The results of the in vivo antihyperglycemic activity assay were in parallel to that of the
in silico studies. The molecular properties of these newer benzamide derivatives were also found
25 to follow the Lipinski’s rule of five for drug-like property. These newly discovered molecules
can serve as the lead molecules for the development of safe, potent and orally active GK
activators as potential type 2 antidiabetic agents.
[0082] The foregoing examples are merely illustrative and are not to be taken as limitations upon
the scope of the invention. Various changes and modifications to the disclosed embodiments will
30 be apparent to those skilled in the art. Such changes and modifications may be made without
departing from the scope of the invention.
19
ADVANTAGES OF THE PRESENT INVENTION
[0083] The present invention provides novel compounds useful as anti-diabetic agents
[0084] The present invention provides glucokinase activators which can overcome
deficiencies associated with the known arts.
5 [0085] The present invention provides novel compounds of Formula I, acting as
glucokinase activators, useful as anti-diabetic compounds.
[0086] The present invention provides novel compounds with high therapeutic activity and
less toxic effects.

We Claim:
1. A compound of Formula I, and its pharmaceutically acceptable salts thereof,
O N^\ /;
H H
O'S"NH-R
Formula I
5 wherein:
R can be selected from H, C1-6alkyl, C3-7cycloalkyl or C6-10aryl; wherein the said C1-6alkyl, C3-
7cycloalkyl, C6-10aryl may optionally be substituted at any available position by one or more
suitable substituents selected from R1;
R1 can be selected from H, C1-6alkyl, C6-10aryl, -OH, -NH2, -CHO, -NO2, -F, -Cl, -Br, -I, -COOH
10 or -CONH2.
2. The compound as claimed in claim 1, wherein R can be selected from C1-6alkyl or C6-
10aryl.
3. The compound as claimed in claim 1, wherein R1 can be selected from H, C1-6alkyl, C6-
10aryl, -OH, -NH2, -NO2, -F or -Br.
15 4. The compound as claimed in claim 1, wherein the compounds is selected from :
Compound No.
1
2
3
4
5
6
7
8
Name
# (1#-1,3 Benzodiazol 2 yl) 3 (phenylsulfamoyl)benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 [(2 chloro 4 nitrophenyl)sulfamoyl]
benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 (benzylsulfamoyl)benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 (butylsulfamoyl)benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 (methylsulfamoyl)benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 [(2 methylphenyl)sulfamoyl]benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 [(4 bromophenyl)sulfamoyl]benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 [(4 nitrophenyl)sulfamoyl]benzamide
21
9
10
N (1H-1,3 Benzodiazol 2 yl) 3 [(4 methylphenyl)sulfamoyl]benzamide
N (1H-1,3 Benzodiazol 2 yl) 3 (propylsulfamoyl)benzamide
5. The compound as claimed in claim 1, wherein compounds of Formula I are prepared by
following steps:
a) chlorosulphonating benzoic acid to obtain 3-(chlorosulphonyl)benzoic acid;
5 b) reaction of 3-(chlorosulphonyl)benzoic acid with different amines to obtain respective
sulphonamides;
c) reacting the sulphonamides obtained in step (b) with SOCl2 to get respective benzoyl
chlorides; and
d) reacting the benzoyl chlorides obtained in step (c) 2-aminobenzimidazole to obtain
10 compounds of Formula I.
6. The compound as claimed in claim 1, wherein the compounds of Formula I act as
allosteric activators of human glucokinase, useful as anti- diabetic compounds.